Organogold(III) complexes containing chelating bis(amidate) ligands: synthesis, characterization and biological activity

Abstract

Reactions of cycloaurated gold(III) dichloride complexes, with 1,2-C6H4(NHCOMe)2 and silver(I) oxide, or with C2H4(NHSO2Tol)2 (Tol = p-tolyl) or 1,2-C6H4(NHSO2Tol)2 and trimethylamine, give a series of new auracyclic complexes containing the Au-NR-CH2CH2-NR (R = SO2Tol) and Au-NR-C6H4-NR (R = COMe or SO2Tol) five-membered ring systems. An X-ray structure determination on (2-bp)Au{N(COMe)C6H4N(COMe)} (2-bp = cycloaurated 2-benzylpyridine) shows the presence of puckered metallacyclic rings, with both acetyl substituents positioned below the Au(III) coordination plane. The complex (2-bp)Au{N(COMe)C6H4N(COMe)} undergoes ring cleavage in the presence of halide and water, to give the complex (2-bp)Au{N(COMe)C6H4NH(COMe)}Cl, which was characterised crystallographically, and shown to contain a monodentate amidate ligand. Biological activity studies of the new auracyclic complexes are also reported, against P388 murine leukaemia cells and a range of bacteria and fungi, with a number of complexes showing high activity.